/*

* SDL_sound -- An abstract sound format decoding API.

* Copyright (C) 2001 Ryan C. Gordon.

*

* This library is free software; you can redistribute it and/or

* modify it under the terms of the GNU Lesser General Public

* License as published by the Free Software Foundation; either

* version 2.1 of the License, or (at your option) any later version.

*

* This library is distributed in the hope that it will be useful,

* but WITHOUT ANY WARRANTY; without even the implied warranty of

* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

* Lesser General Public License for more details.

*

* You should have received a copy of the GNU Lesser General Public

* License along with this library; if not, write to the Free Software

* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

*/

/*

* Module player for SDL_sound. This driver handles anything MikMod does, and

* is based on SDL_mixer.

*

*/

#if HAVE_CONFIG_H

# include <config.h>

#endif

#ifdef SOUND_SUPPORTS_MIKMOD

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "SDL_sound.h"

#define __SDL_SOUND_INTERNAL__

#include "SDL_sound_internal.h"

#include "mikmod.h"

static int MIKMOD_init(void);

static void MIKMOD_quit(void);

static int MIKMOD_open(Sound_Sample *sample, const char *ext);

static void MIKMOD_close(Sound_Sample *sample);

static Uint32 MIKMOD_read(Sound_Sample *sample);

static const char *extensions_mikmod[] =

{

"669", /* Composer 669 */

"AMF", /* DMP Advanced Module Format */

"DSM", /* DSIK internal format */

"FAR", /* Farandole module */

"GDM", /* General DigiMusic module */

"IMF", /* Imago Orpheus module */

"IT", /* Impulse tracker */

"M15", /* 15 instrument MOD / Ultimate Sound Tracker (old M15 format) */

"MED", /* Amiga MED module */

"MOD", /* Generic MOD (Protracker, StarTracker, FastTracker, etc) */

"MTM", /* MTM module */

"OKT", /* Oktalyzer module */

"S3M", /* Screamtracker module */

"STM", /* Screamtracker 2 module */

"STX", /* STMIK 0.2 module */

"ULT", /* Ultratracker module */

"UNI", /* UNIMOD - libmikmod's and APlayer's internal module format */

"XM", /* Fasttracker module */

NULL

};

const Sound_DecoderFunctions __Sound_DecoderFunctions_MIKMOD =

{

{

extensions_mikmod,

"Play modules through MikMod",

},

MIKMOD_init, /* init() method */

MIKMOD_quit, /* quit() method */

MIKMOD_open, /* open() method */

MIKMOD_close, /* close() method */

MIKMOD_read, /* read() method */

MIKMOD_rewind, /* rewind() method */

MIKMOD_seek /* seek() method */

};

/* Make MikMod read from a RWops... */

typedef struct MRWOPSREADER {

MREADER core;

Sound_Sample *sample;

int end;

} MRWOPSREADER;

static BOOL _mm_RWopsReader_eof(MREADER *reader)

{

MRWOPSREADER *rwops_reader = (MRWOPSREADER *) reader;

Sound_Sample *sample = rwops_reader->sample;

Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;

int pos = SDL_RWtell(internal->rw);

if (rwops_reader->end == pos)

return(1);

return(0);

} /* _mm_RWopsReader_eof */

static BOOL _mm_RWopsReader_read(MREADER *reader, void *ptr, size_t size)

{

MRWOPSREADER *rwops_reader = (MRWOPSREADER *) reader;

Sound_Sample *sample = rwops_reader->sample;

Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;

return(SDL_RWread(internal->rw, ptr, size, 1));

} /* _mm_RWopsReader_Read */

static int _mm_RWopsReader_get(MREADER *reader)

{

char buf;

MRWOPSREADER *rwops_reader = (MRWOPSREADER *) reader;

Sound_Sample *sample = rwops_reader->sample;

Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;

if (SDL_RWread(internal->rw, &buf, 1, 1) != 1)

return(EOF);

return((int) buf);

} /* _mm_RWopsReader_get */

static BOOL _mm_RWopsReader_seek(MREADER *reader, long offset, int whence)

{

MRWOPSREADER *rwops_reader = (MRWOPSREADER *) reader;

Sound_Sample *sample = rwops_reader->sample;

Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;

return(SDL_RWseek(internal->rw, offset, whence));

} /* _mm_RWopsReader_seek */

static long _mm_RWopsReader_tell(MREADER *reader)

{

MRWOPSREADER *rwops_reader = (MRWOPSREADER *) reader;

Sound_Sample *sample = rwops_reader->sample;

Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;

return(SDL_RWtell(internal->rw));

} /* _mm_RWopsReader_tell */

static MREADER *_mm_new_rwops_reader(Sound_Sample *sample)

{

Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;

MRWOPSREADER *reader = (MRWOPSREADER *) malloc(sizeof (MRWOPSREADER));

if (reader != NULL)

{

int here;

reader->core.Eof = _mm_RWopsReader_eof;

reader->core.Read = _mm_RWopsReader_read;

reader->core.Get = _mm_RWopsReader_get;

reader->core.Seek = _mm_RWopsReader_seek;

reader->core.Tell = _mm_RWopsReader_tell;

reader->sample = sample;

/* RWops does not explicitly support an eof check, so we shall find

the end manually - this requires seek support for the RWop */

here = SDL_RWtell(internal->rw);

if (here != -1)

{

reader->end = SDL_RWseek(internal->rw, 0, SEEK_END);

if (reader->end != -1)

{

/* Move back */

if (SDL_RWseek(internal->rw, here, SEEK_SET) != -1)

failed_seek = 0;

} /* if */

} /* if */

if (failed_seek)

{

free(reader);

reader = NULL;

} /* if */

} /* if */

return((MREADER *) reader);

} /* _mm_new_rwops_reader */

static void _mm_delete_rwops_reader(MREADER *reader)

{

if (reader != NULL)

free(reader);

} /* _mm_delete_rwops_reader */

static int MIKMOD_init(void)

{

MikMod_RegisterDriver(&drv_nos);

/*

* Quick and dirty hack to prevent an infinite loop problem

* found when using SDL_mixer and SDL_sound together and

* both have MikMod compiled in. So, check to see if

* MikMod has already been registered first before calling

* RegisterAllLoaders()

*/

if (MikMod_InfoLoader() == NULL)

{

MikMod_RegisterAllLoaders();

} /* if */

/*

* Both DMODE_SOFT_MUSIC and DMODE_16BITS should be set by default,

* so this is just for clarity. I haven't experimented with any of

* the other flags. There are a few which are said to give better

* sound quality.

*/

md_mode |= (DMODE_SOFT_MUSIC | DMODE_16BITS);

md_mixfreq = 0;

BAIL_IF_MACRO(MikMod_Init(""), MikMod_strerror(MikMod_errno), 0);

return(1); /* success. */

} /* MIKMOD_init */

static void MIKMOD_quit(void)

{

MikMod_Exit();

md_mixfreq = 0;

} /* MIKMOD_quit */

static int MIKMOD_open(Sound_Sample *sample, const char *ext)

{

Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;

MREADER *reader;

MODULE *module;

Uint32 i; /* temp counter for time computation */

double segment_time = 0.0; /* temp holder for time */

reader = _mm_new_rwops_reader(sample);

BAIL_IF_MACRO(reader == NULL, ERR_OUT_OF_MEMORY, 0);

module = Player_LoadGeneric(reader, 64, 0);

_mm_delete_rwops_reader(reader);

BAIL_IF_MACRO(module == NULL, "MIKMOD: Not a module file.", 0);

module->extspd = 1;

module->panflag = 1;

module->wrap = 0;

module->loop = 0;

if (md_mixfreq == 0)

md_mixfreq = (!sample->desired.rate) ? 44100 : sample->desired.rate;

sample->actual.channels = 2;

sample->actual.rate = md_mixfreq;

sample->actual.format = AUDIO_S16SYS;

internal->decoder_private = (void *) module;

Player_Start(module);

Player_SetPosition(0);

/*

* module->sngtime = current song time in 2^-10 seconds

SNDDBG(("MIKMOD: Name: %s\n", module->songname));

SNDDBG(("MIKMOD: Type: %s\n", module->modtype));

SNDDBG(("MIKMOD: Accepting data stream\n"));

/*

* This is a quick and dirty way for getting the play time

* of a file. This will often be wrong because the tracker format

* allows for so much. If you want a better one, use ModPlug,

* demand that the Mikmod people write better functionality,

* or write a more complicated version of the code below.

*

* There are two dumb ways to compute the length. The really

* dumb way is to look at the header and take the initial

* speed/tempo values. However, speed values can change throughout

* the file. The slightly smarter way is to iterate through

* all the positions and add up each segment's time based

* on the idea that each segment will give us its own

* speed value. The hope is that this is more accurate.

* However, this demands that the file be seekable

* and that we can change the position of the sample.

* Depending on the assumptions of SDL_sound, this block

* of code should be enabled or disabled. If disabled,

* you still can make the computations doing the first method.

* For now, we will assume it's acceptable to seek a Mod file

* since this is essentially how Modplug also does it.

*

* Keep in mind that this will be incorrect for loops, jumps, short

* patterns and other features.

*/

sample->flags |= SOUND_SAMPLEFLAG_CANSEEK;

/*

* For each position (which corresponds to a particular pattern),

* get the speed values and compute the time length of the segment

*/

for (i = 0; i < module->numpos; i++)

{

Player_SetPosition(i);

/* Must call update, or the speed values won't get reset */

MikMod_Update();

/* Now the magic formula:

* Multiply the number of positions by the

* Number of rows (usually 64 but can be different) by the

* time it takes to read one row (1/50)

* by the speed by the

* magic reference beats per minute / the beats per minute

*

* We're using positions instead of patterns because in our

* test cases, this seems to be the correct value for the

* number of sections you hear during normal playback.

* They typically map to a fewer number of patterns

* where some patterns get replayed multiple times

* in a song (think chorus). Since we're in a for-loop,

* the multiplication is implicit while we're adding

* all the segments.

*

* From a tracker format spec, it seems that 64 rows

* is the normal (00-3F), but I've seen songs that

* either have less or are jumping positions in the

* middle of a pattern. It looks like Mikmod might

* reveal this number for us.

*

* According to the spec, it seems that a speed of 1

* corresponds to reading 1 row in 50 ticks. However,

* I'm not sure if ticks are real seconds or this

* notion of second units:

* Assuming that it's just normal seconds, we get 1/50 = 0.02.

*

* The current speed and current tempo (beats per minute)

* we can just grab. However, we need a magic number

* to figure out what the tempo is based on. Our primitive

* stopwatch results and intuition seem to imply 120-130bpm

* is the magic number. Looking at the majority of tracker

* files I have, 125 seems to be the common value. Furthermore

* most (if not all) of my Future Crew .S3M (Scream Tracker 3)

* files also use 125. Since they invented that format,

* I'll also assume that's the base number.

*/

if(module->bpm == 0)

{

/*

* Should never get here, but I don't want any

* divide by zero errors

*/

continue;

} /* if */

segment_time += (module->numrow * .02 * module->sngspd *

125.0 / module->bpm);

} /* for */

/* Now convert to milliseconds and store the value */

/* Reset the sample to the beginning */

Player_SetPosition(0);

MikMod_Update();

return(1); /* we'll handle this data. */

} /* MIKMOD_open */

static void MIKMOD_close(Sound_Sample *sample)

{

Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;

MODULE *module = (MODULE *) internal->decoder_private;

Player_Free(module);

} /* MIKMOD_close */

static Uint32 MIKMOD_read(Sound_Sample *sample)

{

Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;

MODULE *module = (MODULE *) internal->decoder_private;

/* Switch to the current module, stopping any previous one. */

Player_Start(module);

if (!Player_Active())

{

sample->flags |= SOUND_SAMPLEFLAG_EOF;

return(0);

} /* if */

return((Uint32) VC_WriteBytes(internal->buffer, internal->buffer_size));

} /* MIKMOD_read */

static int MIKMOD_rewind(Sound_Sample *sample)

{

Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;

MODULE *module = (MODULE *) internal->decoder_private;

Player_Start(module);

Player_SetPosition(0);

return(1);

} /* MIKMOD_rewind */

static int MIKMOD_seek(Sound_Sample *sample, Uint32 ms)

{

Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;

MODULE *module = (MODULE *) internal->decoder_private;

double last_time = 0.0;

double current_time = 0.0;

double target_time;

Uint32 i;

/*

* Heaven may know what the argument to Player_SetPosition() is.

* I, however, haven't the faintest idea.

*/

Player_Start(module);

/*

* Mikmod only lets you seek to the beginning of a pattern.

* This means we'll get very coarse grain seeks. The

* value we pass to SetPosition is a value between 0

* and the number of positions in the file. The

* dumb approach would be to take our total_time that

* we've already calculated and divide it up by the

* number of positions and seek to the position that results.

* However, because songs can alter their speed/tempo during

* playback, different patterns in the song can take

* up different amounts of time. So the slightly

* smarter approach is to repeat what was done in the

* total_time computation and traverse through the file

* until we find the closest position.

* The follwing is basically cut and paste from the

* open function.

*/

if (ms == 0) /* Check end conditions to simplify things */

{

Player_SetPosition(0);

return(1);

} /* if */

Player_SetPosition(module->numpos);

/* Convert time to seconds (double) to make comparisons easier */

target_time = ms / 1000.0;

for (i = 0; i < module->numpos; i++)

{

Player_SetPosition(i);

/* Must call update, or the speed values won't get reset */

MikMod_Update();

/* Divide by zero check */

if(module->bpm == 0)

continue;

last_time = current_time;

/* See the notes in the open function about the formula */

current_time += (module->numrow * .02

* module->sngspd * 125.0 / module->bpm);

if(target_time <= current_time)

break; /* We now have our interval, so break out */

} /* for */

if( (target_time-last_time) > (current_time-target_time) )

{

/* The target time is closer to the higher position, so go there */

Player_SetPosition(i+1);

} /* if */

else

{

/* The target time is closer to the lower position, so go there */

Player_SetPosition(i);

} /* else */

#endif /* SOUND_SUPPORTS_MIKMOD */

/* end of mikmod.c ... */